A double-sided PCB has conductive copper on both sides of its insulating base. The term describes the board’s conductive construction, not a requirement to mount components on both sides. A two-layer board can carry components on one side, and assembly requirements should be specified separately.
Check what connects the two sides
Where the design requires electrical connections through the board, identify the plated holes and their intended function. Mechanical holes may have different requirements. The fabrication data should distinguish these categories rather than leaving the factory to infer them from the artwork.
Eurocircuits’ drilled-hole guidance distinguishes hole information and finished-hole conventions within its manufacturing service. Use the selected factory’s documented requirements to communicate your design, particularly when a hole must fit a component lead or mechanical part.
Prepare a concise fabrication drawing
| Item | What to make unambiguous |
|---|---|
| Board outline | Finished contour, slots and critical dimensions |
| Holes | Plating status, finished size and relevant tolerances |
| Construction | Material, finished thickness and copper requirements |
| Surface finish | Finish required on exposed solderable areas |
| Acceptance | Agreed inspection and electrical test records |
Use tolerances according to the function. A dimension that controls a connector fit deserves explicit attention, while unnecessarily restrictive dimensions elsewhere may complicate purchasing without improving the product.
Review routing and assembly as separate constraints
Two copper layers offer routing options beyond a single conductive layer, but they do not automatically double component capacity or satisfy every complex circuit. Evaluate the actual placement, routing and signal requirements before choosing the construction.
If components are fitted on both sides, ask the assembler to review access, support and process sequence. The bare-board factory’s ability to make two copper layers does not by itself establish that the assembled product is straightforward to build.
Evaluate the factory’s technical response
Ask the supplier to review the complete manufacturing package and identify any assumptions. Compare quotations for the same material, thickness, copper and acceptance scope. A generic “two-layer PCB” price may conceal differences that matter to your application.
For the first order, check fit-critical dimensions and the supplied records against the approved drawing. Record any accepted deviations and update the release if a permanent change is intended.
Preserve the final data package with the order number. This makes a repeat order or supplier transfer easier to review than reconstructing the design from an old quotation and several email attachments.
Primary reference: Eurocircuits drilled-hole guidance. See the PCB manufacturing planning guide.
Move from reading to a build-ready project
Use the fabrication and assembly checklists to prepare drawings, production files and test requirements.
Open the DFM checklist